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[v8,16/28] mm: Allow arm64 mmap(PROT_MTE) on RAM-based files

Message ID 20200824182758.27267-17-catalin.marinas@arm.com (mailing list archive)
State New, archived
Headers show
Series arm64: Memory Tagging Extension user-space support | expand

Commit Message

Catalin Marinas Aug. 24, 2020, 6:27 p.m. UTC 
Since arm64 memory (allocation) tags can only be stored in RAM, mapping
files with PROT_MTE is not allowed by default. RAM-based files like
those in a tmpfs mount or memfd_create() can support memory tagging, so
update the vm_flags accordingly in shmem_mmap().

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/shmem.c | 3 +++
 1 file changed, 3 insertions(+)
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Patch

diff --git a/mm/shmem.c b/mm/shmem.c
index 271548ca20f3..ec94f4c7851e 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2267,6 +2267,9 @@  static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
 			vma->vm_flags &= ~(VM_MAYWRITE);
 	}
 
+	/* arm64 - allow memory tagging on RAM-based files */
+	vma->vm_flags |= VM_MTE_ALLOWED;
+
 	file_accessed(file);
 	vma->vm_ops = &shmem_vm_ops;
 	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&